Pyrocatechol its sulfonic acid is often present in the urine of many mammals. Small amounts of catechol occur naturally in fruits and vegetables along with the enzyme polyphenol oxidase. Upon mixing the enzyme with the substrate and exposure to oxygen (as when a potato or apple is cut) the colorless catechol oxidizes to reddish-brown benzoquinone derivatives.

Alanine is an Amino Acid. The chemical classification of alanine is Amino Acids. Alanine is a small non-essential amino acid in humans.

Djenkolic Acid is a naturally occurring sulfur-containing amino acid extracted from djenkol beans(Archidendron pauciflorum), which is native to Southeast Asia.